Coinfection

Among HBV/HCV coinfected people, about half have dominant hepatitis B virus while half have dominant hepatitis C, and those with active HBV replication are at higher risk of liver-related complications and death, according to study findings presented at Digestive Disease Week this month in Chicago.

Due to similar routes of transmission, many people are coinfected with both hepatitis B virus (HBV) and hepatitis C virus (HCV). Previous research has shown that the 2 viruses can interact with one another, with HBV suppressing HCV replication and vice versa. Patterns of viral dominance are unpredictable, however, and their effects on clinical outcomes are unclear.

Robert Kruse from the Center for Innovations in Quality, Effectiveness and Safety and colleagues conducted a retrospective cohort study of hepatitis C patients who received care at through the U.S. Veterans Administration health system between 1997 and 2005.

Among nearly 103,000 patients identified with detectable HCV RNA viral load, 1431 -- or about 1.4% -- had HBV coinfection as determined by positive hepatitis B surface antigen, hepatitis B "e" antigen, or detectable HBV DNA. Almost all were men, about half were white, about one-third were African-American, and the mean age was 49 years.

HBV/HCV coinfected patients were classified as having HBV dominance if they had detectable serum HBV DNA as well as detectable HCV RNA. Those who had undetectable HBV DNA were considered to have HCV dominance.

Coinfected patients with HBV dominance had the highest relative risk of adverse outcomes including liver cirrhosis, hepatocellular carcinoma (a form of liver cancer), and mortality.

In a multivariate analysis adjusting for demographics and other factors including HIV infection and alcohol use, coinfected patients with HBV dominance had worse outcomes than HCV monoinfected people:

o Cirrhosis: adjusted hazard ratio (HR) 2.15, or more than twice the risk;

o Hepatocellular carcinoma: adjusted HR 1.97;

o Death: adjusted HR 1.37.

However, there were no significant differences in the risk of cirrhosis, liver cancer, or death between HBV/HCV coinfected patients with HCV dominance and those with HCV alone.

"In patients with HCV/HBV coinfection, HBV was dominant in approximately 50% of the patients who were tested for HBV DNA," the researchers concluded. "Presence of active HBV replication resulted in significantly worse outcomes in HCV/HBV coinfected patients. In contrast, absence of HBV replication was associated with a clinical course similar to that of HCV monoinfected patients."